Tuning device



Patented May 6, 1941 UNITED STATES PATENT OFFICE TUNING DEVICE Gobi Walder, Zurich, Switzerland Application October 18, 1939, Serial No. 300,080

3 Claims.

The invention relates to tuning devices for string instruments. The known tuning devices hitherto had the disadvantage that a fine adjustment was not possible. Further they have the disadvantage that they are easily displaced and that when tuning to another pitch, for example from the major key to the minor key, there occurs either a variation of the length of vibration or the position in height of the strings. By a variation of the length of vibration, the timbre of the string is influenced and a variation of the position in height of the strings is disadvantageous when playing. These disadvantages are adapted to be eliminated according to the invention in that for the variation of the tension of the separate strings there are provided between their two points of securing, two supporting points for the strings and an eccentric reversing lever, whereby the reversing lever acts on the string with its eccentrically shaped part between the two supporting points. The free end of this eccentric lever is subjected to the action of a fine adjustment. In this manner it is possible to effeet a tuning at the free end of the lever by hand and the prevailing adjustment is secured by means of the fine adjustment. It is also possible to effect the tuning solely by actuating the fine adjustment of which the movement also effects a movement of the eccentric lever.

The string to be tuned can be drawn preferably, according to the invention, over two bearing bodies of the device. Further the string passes under the rotatable eccentric which is located between the bearing bodies. At the lower part of the device is preferably provided with projections which engage in suitable recesses in the string instrument. In this manner there is not only obtained a sufiiciently firm mounting on the instrument. The said projections also prevent contact taking place between the strings and the instrument.

Between the eccentric and the string there is preferably mounted a steel plate or a similar plate. This plate may be secured at one end to a suitable bearing pin of the device, whilst the other end hangs freely downwardly. This plate prevents the string from being worn by moving the lever. The said fine adjustment may consist .of a micrometer screw which acts at its free end on the lever. The screw is secured to the device in a nut-like body. A fixing device in the form of a clamping screw is preferably also provided.

An example of construction of the invention to an enlarged scale is shown in the accompanying drawing, wherein:

Fig. 1 shows a perspective of the tuning device. Fig. 2 is a section on the line II-II of Fig. 3. Fig. 3 is a plan.

In the body I is provided a slot 2. With this slot 2 there engages the string 3 to be tuned. The string 3 bears at the front end against the bearing bolt 4 and at the rear end against the bearing bolt 5. At about the middle of the device there is mounted, on a pin 1, the eccentric 6. At 9 there is mounted a spring blade l0. Between the string 3 and the eccentric 6 there is located the free end of the spring blade l0 so that when moving the eccentric 6 by means of the handle II or by means of the micrometer screw 12 adjustably mounted at l3, the eccentric 6 produces a variable tension of the string 3. The micrometer screw 12 is actuated by turning the knob I4. The lock nut 15 serves for locking the micrometer screw in the adjusted position. As will be seen clearly from the drawing the free end of the micrometer screw l2 acts on the lever arm ll of the eccentric 6.

In Figure 2, the instrument is represented by IS, the pins to which the ends of the wire 3 are fastened are indicated by I! and I8, and the recesses in the instrument for the projections 20 are indicated by I9.

I claim:

1. A tuning device comprising a body having a slot in which the string to be tuned may lie, two cross bolts carried by said body in said slot and over which the string lies, an eccentric pivotally mounted in said slot at a place intermediate the location of said cross bolts and under which the string lies in cooperative proximity to the eccentric, a lever extending from said eccentric, and a fine adjustment screw mounted on said body and engaging said lever to adjust the position of said eccentric.

2. A tuning device comprising a body having a slot in which the string to be tuned may lie, two cross bolts carried by said body in said slot and over which the string lies, an eccentric pivotally mounted in said slot at a place intermidiate the location of said cross bolts and under which the string lies, a lever extending from said eccentric, a fine adjustment screw mounted on said body and engaging said lever to adjust the position of said eccentric, and a spring blade located in said slot between the string and said eccentric and in contact with the same.

3. A tuning device comprising a body having a slot in which the string to be tuned may lie, two cross bolts carried by said body in said slot and over which the string lies, an eccentric pivotalcated in said siot between the string and said eccentric and in contact with the same, one end of said blade being anchored to said body and the other end of the same being free.

GOBI WALDER. 

